OLENELLUS AND OTHER GENERA .OF MESONACID^ 365 



Elliptocephala asaphoides Emmons (continued) : page 



13. A small convex cephalon. X 3- Locality (38a), near North 



Granville, Washington County, New York. U. S. National 

 Museum, Catalogue No. 15413?. 



14. A large flattened cephalon from the limestone in locality (36), 



3.5 miles north of Cambridge, Washington County, New York. 

 This approaches in form the specimens from the shale at 

 Greenwich [pi. 24, fig. i]. Natural size. U. S. National 

 Museum, Catalogue No. 15413;. 



15. Top and side view of a somewhat compressed cephalon in lime- 



stone for comparison with the cephalon of fig. i, pi. 24, which 

 is flattened in the shale. Natural size. Locality (45&), near 

 Low Hampton, Washington County, New York. U. S. Na- 

 tional Museum, Catalogue No. is^izk. 



16. Marginal borders, base of genal spine, and portion of cheek 



showing surface markings. X 3- Locality (290), near Scho- 

 dack Landing, Rensselaer County, New York. U. S. National 

 Museum, Catalogue No. 154140. 



17 and 17a. Top and side view of a thoracic spine occurring in lime- 

 stone. X 2. Locality (38a), North Granville, Washington 

 County, New York. U. S. National Museum, Catalogue No. 

 15413^- 



18. Thoracic spine. X i-5- From locality (27), near Troy, Rensse- 

 laer County, New York. U. S. National Museum, Catalogue 

 No. 15413m. 



This spine was illustrated as the telson of this species by 

 Walcott. 1886, pi. 17, fig. 3. 



Padeumias transitaiis, new genus and new species (See pis. 24, 32, 25, 34. 



41, and 44) 305 



Figs. 19, 20, and 21. Small cephalons showing genal and intergenal spines, 

 cylindrical glabella, large eye lobes, and in fig. 21 the rounding- 

 in of the genal angles. No. 20, X 9; No. 21, X 8; and No. 22, 

 X 13- U. S. National Museum, Catalogue Nos. 568090, 568096, 

 and 568o9f, respectively. 



22. Cephalon with strong protaspis characters. The genal and 

 intergenal spines are practically merged into single spines and 

 the frontal lobe of the glabella nearly merged into the eye 

 lobes. X 30. U. S. National Museum, Catalogue No. 56809^. 

 The genal and intergenal spines in the young cephalons of 

 Elliptocephala asaphoides have t.ie same tendency as those of 

 this species [see pi. 25, figs. 9 and 10]. 



The specimens illustrated by figs. 20-22 are from locality 

 (56c), near Helena, Shelby County, Alabama. 



